I. Definitions
As used herein, the phrase “group III-V” refers to a compound semiconductor that includes a group V element and at least one group III element. Moreover, the phrase “III-Nitride”or “III-N” refers to a compound semiconductor that includes nitrogen (N) and at least one group III element, including aluminum (Al), gallium (Ga), indium (In), and boron (B), and including but not limited to any of its alloys, such as aluminum gallium nitride (AlxGa(1-x)N), indium gallium nitride (InyGa(1-y)N), aluminum indium gallium nitride (AlxInyGa(1-x-y)N), gallium arsenide phosphide nitride (GaAsaPbN(1-a-b)), and aluminum indium gallium arsenide phosphide nitride (AlxInyGa(1-x-y)ASaPbN(1-a-b)), for example. III-Nitride also refers generally to any polarity including but not limited to Ga-polar, N-polar, semi-polar or non-polar crystal orientations. A III-Nitride material may also include either the Wurtzitic, Zincblende, or mixed polytypes, and may include single-crystal, monocrystalline, polycrystalline, or amorphous structures.
II. Background Art
Group III-V semiconductors, such as gallium nitride (GaN) or other III-Nitride materials, are used in many microelectronic implementations in which high power density and high efficiency switching are required. Examples of such implementations include field-effect transistors (FETs) and high electron mobility transistors (HEMTs).
Although the intrinsic material properties of III-Nitride semiconductors enable fabrication of high performance devices in theory, as a practical matter, conventional growth environments for III-Nitride materials typically include impurity sources. The presence of those impurity sources in the III-Nitride growth environment can cause unintentional doping of critical device layers. In HEMTs, for example, as well as in other high speed switching devices, such unintentional impurity doping may adversely compromise device performance.